Underwater breathing apparatus



April 1, 1958 R. KIMES 2,

UNDERWATER BREATHING APPARATUS Filed May 5, 1954 2 Sheets-Sheet 1 28ROBERT K/MES;

INVENTOR.

April 1, 1958 R. KIMES 2,828,739

UNDERWATER BREATHING APPARATUS Filed May 3, 1954 ZSheets-Sheet 2 Fig.3.

' 3 *w, so 8 7 l5 ROBERT K/MES,

INVENTOR,

BY #7. W

United States Patent UNDERWATER BREATHING APPARATUS Robert Kimes, CulverCity, Calif., assignor to The Garrett Corporation, Los Angeies, Calif.,a corporation of California Application May 3, 1954, Serial No. 427,195

20 Claims. (1. 128-442) The present invention relates generally torespiration devices, and relates more specifically to an improved deviceproviding a low breathing resistance, whereby such device may be moreeasily and more comfortably used by a person.

The improvements according to this invention are intended for use withrespiration devices of the type disclosed herein or may be used inconnection with devices of the type disclosed in the co-pendingapplication of Kimes et al., Serial No. 378,856, filed September 8,1953.

Heretofore, breathing devices adapted primarily for use under water haveincorporated various means for delivering a controlled quantity of abreathable gas in response to respiration induced changes in thepressure within the device, the gas being delivered at a pressuresuitable for use in the lungs of an individual. ditions, such assteadily dropping pressure of the usual bottled supply of breathable gasand variation in the depth at which the device is being utilized,constant changes in operating characteristics of the breathing deviceswere experienced. These changing characteristics resulted in undesirablyincreased breathing resistance. More specifically, in prior devices, arespiration pressure-responsive diaphragm, exposed on one side to thepressure of the surrounding fluid medium and on the other side to thepressure of a breathable gas, has been used to operate a valve foradmiting breathable gas from a source to the point of use. Such deviceshave incorporated floating valve seat arrangements, operable inassociation with the valve, and with the .rms of valve operating leversvariable in attitude or presentation to the floating valve seat andrelative to a normal position of the diaphragm. Means utilized in suchdevices for transmitting the movement of the diaphrgam, and for openingthe valve member, necessarily changed the operating characteristcisthereof as the valve member was moved in accordance with movement of thefloating valve seat relative to the diaphragm. This conditionnecessarily increased breathing resistance, because in certain attitudeof the levers it required considerable movement of the diaphragm beforethe valve member became adequately open.

It is accordingly an important object of the present invention toprovide a novel breathing device having means adapted to overcomedisadvantages in prior devices, as set out hereinabove.

It is another object of the present invention to provide a novelunder-water breathing device wherein efficient use is made ofrespiration induced movement of a movable wall for efiecting opening ofa breathable gas-control valve member.

A further object of the invention is to provide a novel actuating meansfor a valve member wherein the force required to open the valve memberis directly proportional to the pressure of a breathable gas obtainedfrom a source.

It is a still further object of the present invention to provide abreathing device wherein the necessary tolerances may be satisfactorilyheld without the necessity for Due to varying con- 2,828,739 PatentedApr. 1, 1958 ice precision manufacturing of components or calibration ofi the finished device.

invention, taken substantially as indicated by the line 3-3, Fig. 2;

Fig. 4 is a fragmentary perspective view, partially in section, showingdetails of the floating valve seat, valve member and operating meanstherefor; and

Fig. 5 is a fragmentary end view of the reserve valve operating leverand associated cam structure.

Referring to the drawings, wherein like reference characters denote likeparts, the berathing apparatus of the present invention is indicatedgenerally at 10. The apparatus includes a regulator 11 mounted inassociation with a bottle or tank 12 which contains a supply ofbreathable gas under pressure. The regulator 11 is uperatively connectedto a mouthpiece 13 by a flexible inhalation conduit 14 and a similarflexible exhalation conduit 15.

The regulator is provided with a substantially annular body 16 havinglaterally extending bosses 17 and 18 to which the inhalation andexhalation conduits 14and 15 are respectively connected by clamp rings20. A disclike cap 21, forming an outer chamber 22, and a plurality ofradially directed openings 23 communicate between the I chamber 22 andthe exterior of the regulator. The cap 21 is secured to the body 16 byscrews 24 and serves to retain a flexible diaphragm 25, the peripheralportion of the diphragm 25 being disposed between the body 16 and thecap 21.

The diaphragm 25 provides a movable wall for one side of a chamber 26,formed within the body 16 of the regulator, for a purpose to behereinafter more fully described. The diaphragm 25 is clamped between apair of annular stiffening plates 27 and 28 that are secured together byrivets 30. The diaphragm and the plates 27 and 28, are formed with acentrally disposed opening 31 in which an exhalation valve insert 32 isadapted to be disposed. The insert 32 has a radially extending flangeportion 33 adjacent the chamber 26, which overlies a portion of theplate 27 adjacent the opening 31 to retain the insert 32 in position.The insert 32 is also provided with an axially extending peripheralflange 34 which extends into the chamber 22. A plurality of spacedopenings 35 extend in an axial direction through the insert 32.

A flexible exhalation valve 36 is positioned in association with theinsert 32 and has a centrally disposed button 37 which is received in asimilarly shaped opening 38 in the insert 32. The valve member 36 has aflexible peripheral portion 40 that normally lies in con tact with anannular valve seat 41 formed on the outer surface of the insert 32 andspaced radially inwardly from the peripheral flange 34. The insert 32and the valve member 36 may be made from rubber or other flexiblematerial and cooperate to permit fluid flow only outwardly from thechamber 26 by way of the passages 35, the peripheral flexible portion40, chamber 22 and openings 23 to the surrounding fluid medium.Additional operation and detailed use of the valve member 36 will bemore fully described hereinafter. The side of the chamber 26, oppositethe diaphragm 25, is occluded by a fixed disc 42 that is secured to thebody 16 by screws 43. The disc 42 also forms a fixed wall for asecondarychamber 44 formed in the lower portion of the body 16. The chamber 44communicates with the conduit 14 by a bore 45, formed outwardly throughthe boss 17, and the chamber 26 communicates with the conduit through abore 46, extending outwardly through the boss 18.

A floating valve seat arrangement, indicated generally at 47, ispartially disposed within the chamber 44 to which breathable gas fromthe tank 12 is delivered through a reserve air valve arrangement 48.Referring primarily to Figs. 1 and 2, breathable gas from the tank 12delivered through a shut-off valve 50, attached to one end of tank 12,and into a receiving opening 51 by a fitting 52. The fitting 52 issecured to the valve by a yoke 53 which is in turn secured to the valve50 by a set screw 54. From the opening 51, the gas is conducted througha passageway 55, extending outwardly through a boss 56, to a chamber 57formed adjacent an inner end of a nut 58. The nut 58 threadably engagesthe boss 56 by threads 60 and is sealed with respect to the boss 56 byan annular sealing member 61 disposed in an annular groove 62 formed inthe periph cry of the nut 58.

The reserve air valve arrangement 48 comprises a multi-purpose elongatedmember 63 that has a shaft portion 64 slidably disposed in an axial bore65 formed through the nut 58. An annular sealing member 66 disposedabout the shaft 64 seals the shaft relative to the bore 65. v For apurpose to be hereinafter more fully described, the outer end of theshaft 64 is secured to an external lever 67 by a nut 68. The inner endof the member 63 is provided with a reduced diameter piston portion 70that is slidably received in a bore 71, there being an increaseddiameter piston 72 disposed between the piston 70 and the shaft 64, thepiston 72 being slidable in a bore 73. The bores 71 and 73 are coaxialwith each other and have a common axis with the nut 58. The pistons 70and 72 are sealed by sealing rings 74 and 75-respectively, which aredisposed about their periphcries.

The breathable gas from the chamber 57 is conducted through'radiallyextending passageways 76 in the mem ber63, adjacent the piston 72, andthrough an axially extending passageway 77 disposed between the passageways 76 and the inner end of the piston 70. This inner end of thepassageway 77 is formed with a conical valve seat 78, there being areserve air valve member 80 positioned for cooperation with the seat 78.The valve member 80 is biased in a direction toward the seat 78 by acompression spring 81. The other end of the. spring 81 bears against thebody 16.

The member 63, including the pistons 70 and 72, is adapted to remainnormally in the position shown in Fig. 2 by virtue of the pressuredilferential acting thereon and in accordance with the difierential inthe areas of the pistons 70 and 72. The member 63 is adapted formovement away or outwardly from the nut 58 by rotation of the lever 67acting in cooperation with a cam portion 82 of a member 83, the cammember 83 being secured to the outer end of the boss 56 by a flangedportion 84 formed on the outer end of the nut 58. Outwardmovement of themember 63 is limited by a stop 79 formed on the shaft portion 64adjacent the enlarged portion 72 and adapted to cooperate with the innerend of the nut 58. v The cam member 83 is held against ro- P pressionspring 81 acting normally to bias the valve member 80 toward the valveseat 78.

The breathable gas flowing about the valve member 80, and within thebore 71, passes through an opening 87, and into an annular passageway88, Fig. 3. The passageway 88 is formed partially in the outer surfaceof a floating valve seat piston 90 and partially in a bore 91 in whichthe upper portion of the piston 90 is reciprocally positioned. Thepiston 90 has a reduced diameter end 92 that is positioned for movementin a reduced diameter counterbore 93 formed coextensively with the bore91. It may be seen that the upper portion of the piston 90 has a largereffective area than the area of the reduced diameter portion 92, therebypermitting the pressure of the breathable gas existing in the annularpassageway 88 to bias the piston 90 and the floating valve seatarrangement 47 in an upward direction, as shown primarily in Fig. 3. Thelower end of the bore 93 is vented to the chamber 44 by a ventpassageway 94, the piston 90 and reduced diameter end 92 being sealedwith respect to the bores 91 and 93 by annular sealing members 95 and 96respectively. By providing the vent passageway 94, air is prevented frombeing compressed in the lower end of the bore 93 and any leakage pastthe sealing member 96 may be readily detected.

A plurality of radially extending bores 97 conduct the breathable gasfrom the annular passage 88 to an axially disposed passageway 98 formedwithin the piston 90, the upper end of the passageway 98 being providedwith a conical valve seat 100. An elongated valve member 101, having avalve portion 102, cooperates with and normally occludes the upper endof the passageway 98. A compression spring 103, surrounding the valvemember 101 and bearing between one side of the disc 42 and the valveportion 102, serves to bias the valve member 101 toward contact-with theseat 100. An annular guide member 104, extending axially upwardly fromthe piston 90, serves to guide the valve portion 102 of the valvemember. The upper portion of the valve member 101 is reciprocallypositioned in an axial opening 105 in the disc 42.

A radially extending flange 106-is formed on the upper end of the piston90, the peripheral portion of the flange 106 being rotatably retained inone end of a cylindrical fulcrum supporting member 107 and positionedthereinby inwardly directed tabs 108. The fulcrum supporting member 107has large side openings 110 which communicate between the interior ofthe member 107 and the chamber 44 thereby permitting the flow ofbreathable gas from the passageway 98, past the valve portion 102, intothe interior of the member 107, outwardly through the openings 110 andinto the chamber 44. A relatively heavy compression spring 111 isdisposed within the fulcrum supporting member 107, between the disc 42and the flange 106, in order to bias the floating valve seat against theforce exerted by the breathable gas in the annular passageway 88 againstthe pressure differential areas of the piston 90.

The fulcrum supporting member 107 has a plurality of upwardly extendingfulcrum members 112 which extend through spaced arcuate slots 113through the disc 42 (see also Fig. 4). The upper end of the valve member101, i. e., the portion extending within the chamber 26, is providedwith a radially extending head portion in the form of a disc 114 whichis secured to the upper end of the valve member by a snap ring 115. Aplurality of actuating levers 116 are disposed in and extend throughnotches 117, formed in the upper ends of the fulcrum members 112, therebeing cooperating opposed notches 118 oneach side of the levers 116which serve to retain the levers within the notches 117. The inner ends120 of the levers 116 extend beneath the disc 114. The levers 116 extendsubstantially radially outwardly with their outer ends 121 engaging thediaphragm stiffening plate 27 adjacent the periphery thereof. It maytherefore be seen that, as the diaphragm 25 moves inwardly toward thechamber 26, the outer ends 121 of the levers 116 will be moveddownwardly, thus moving their inner ends 120 upwardly, thereby to movethe valve member 101 upwardly against the compression of the spring 103.This action serves to remove the valve portion 102 from the valve seat100 and permit flow of breathable gas outwardly from the axialpassageway 98.

The mouthpiece 13 of the present breathing device has a flexible lipengaging portion or bit 122 that is adapted for insertion within themouth of a user. The hollow body portion 123 of the mouthpiece has endportions which are attached respectively to the inhalation andexhalation conduits 14 and 15. There is unrestricted communicationbetween the mouthpiece ends of the conduits 14 and 15 and a flow passage124 which is formed in the lip engaging portion 122. It is the usualpractice for the tank 12 (or a plurality of tanks arranged for paralleloperation) to be fastened to the back of the user by means of' aharness, not shown, with the regulator 11 being in the approximateposition shown in Fig. 1. A lanyard 125 is attached to the reserve airvalve lever 67 and extends through suitable guides 126 formed on thehardness to a ring 127 or the like, the ring being positioned for easyaccess thereto.

Prior to descending into Water, the user opens the valve 50 on the tank12 thereby admitting breathable gas through the various flow passages ofthe reserve air valve arrangement 48 and to the passageway 98 of thefloating valve seat arrangement 47. At this time, the floating valveseat will be in its uppermost position compressing the spring 111 andmetering valve spring 103, the fulcrum members 112 being in theiruppermost position with respect to the disc 42. It will be seen that thevalve member 101 together with the washer 114 is also in its uppermostrange. The stifiening plate 27 of the diaphragm 25 will contact theouter ends 121 of the levers 116. The exhalation valve 36 will beclosed.

When entry is made into the water, it is to be noted that the pressureof the surrounding water acts upon the outer surface of the diaphragm25, by entry of the water through the openings 23 in the cover 21, andthat the pressure within the chamber 26 acts upon the other side of thediaphragm 25. As the pressure of the surrounding medium increases, apressure difierential is manifested across the diaphragm 25 therebycausing the diaphragm to move inwardly toward the chamber 26 and,through the levers 116 causing opening of the valve member 101 and theadmission of breathable gas to the chamber 44, passage 45, conduit 14,through the mouthpiece 13, the conduit 15 and into the chamber 26 by wayof the passage 46. The flow of the breathable gas along theaforementioned path will continue until the pressure of the gas in thechamber 26 equals that of the surrounding fluid medium, whereupon thediaphragm 25 will move outwardly thus permitting the valve member 101 tobe closed by action of the compression spring 103.

It is the usual practice to begin use of the present breathing apparatuswith compressed air at a high pressure, 3,000 p. s. i., for example, inthe tank 12. This pressure, minus a pressure drop across the reserve airvalve 48, is also manifested in the annular passageway 88 thus to movethe fulcrum supporting member 107 to its uppermost position bycompression of the spring 111. It will be seen that, as the breathablegas from the tank 12 is consumed, the force exerted on the piston 90will be decreased, thereby permitting the floating valve seat and thepiston 90, together with the fulcrum supporting member 107, to be moveddownwardly by action of the spring 111. As the piston 90 movesdownwardly, the etiective force of the spring 103 is reduced, thusreducing the force which retains the valve portion 102 of the valvemember,

6 101 on the valve seat 100. -In the initial position, with breathablegas at a high pressure available from the tank 12, the force of thespring 103 need be only sufliciently higher than the force of thebreathable gas acting upon the end of the valve portion 102 to maintainthe valve portion 102 in contact with the valve seat 106. Ashereinbefore stated, as the available pressure of the breathable gas isreduced due to consumption thereof, movement of the floating valve seatarrangement downwardly by action of the spring 111 will maintain theforce of the spring 103 just slightly higher than the force of thebreathable gas acting in a direction to open the valve member.

Concurrent with movement of the fulcrum supporting member 107 in adownward direction, due to reduced pressure of the breathable gas fromthe source, the fulcrum member 112 will also move downwardly, thus tomaintain the fulcrums for the levers 116 within a constant range ofdistance from the radially extending disc 114 on the upper end of thevalve member 101 and from the diaphragm stiffening plate 27. Thismaintenance of prescribed distance range serves to maintain constant theforce, or in other words, the breathing efiort, required to move thelevers 116. This compensating action is in distinction to that in priordevices wherein the attitude assumed by the lever arms changes as theranges of distance change between, respectively, the valve member andthe fulcrums and the diaphragm and the fulcrums, thus increasing theforce required to lift the valve as the supply pressure drops andthereby increasing the breathing resistance. I

Upon inhalation by the user, a reduction in pressure will be created inthe flexible conduits'14 and 15 and in the chambers 44 and 26 thereby tocause the diaphragm 25 to move inwardly toward the chamber 26, raise thevalve portion 102 from the valve seat 100 and admit breathable gas tothe chamber 44 and inhalation conduit 14. The pressure of the breathablegas admitted to the chamber 44 is determined by the extent of movementof the diaphragm 25 and the effective space between the valve portion102 and the valve seat100. It is to be noted that the reserve air valvemember normally is positioned to occlude the inner end of the passageway77 and to open when a pressure differential exists across the valvemember 80. Such a condition will exist upon inhalation or whenever thevalve portion 102 is lifted from the valve seat 130.

Upon exhalation, exhalation gases will be transmitted to the mouthpiece13 and through the exhalation conduit 15 to the chamber 26 therebyincreasing the pressure within the chamber 26 and moving the diaphragm25 outwardly until the central portion of the exhalation valve 36contacts an inner surface 128 of the cover 21. When contact is madebetween the valve 36 and the cover 21, the peripheral portion 40 of theexhalation valve 36 will be flexed outwardly, thereby permitting flow ofexhalation gases outwardly through the passages 35 to the surroundingfluid medium. in submarine usage the raisedflango 34 on the insert 32serves to prevent surging water from entering the chamber 26 beneath theedges 40 of the exhalation valve 36.

It is to be noted that, upon exhalation, a slight rise in pressure willalso occur in the conduit 14; however, no flow will occur in thisconduit inasmuch as the valve portion 102 is in a closed position.Additionally, upon inhalation, it is to be further noted that little orno reverse flow will be experienced in the exhalation conduit 15 therebyeliminating so-called pendulum breathing or re-breathing of exhalationproducts.

When the pressure of the breathable gas in the tank 12 reaches apredetermined low limit, approaching exhaustion, the force of thereserve air valve spring 81 will be such as to effect closure of thevalve member 80. This closure occurs when the difierential across thevalve member 80 is insufiicient to permit the valve member to open withnormal breathing. In most instances, the force of the spring 81 is setto accomplish such closure of the valve member 89 when the pressure ofthe breathable gas from the source drops to 300 p. s. i., for example.The closure of the valve member 8i) at this point makes breathing verynoticeably more difficult and serves as a warning to the user that thesupply of breathable gas is approaching exhaustion, whereupon the ring127 is grasped to pull the lanyard 125 and rotate the lever 67 in orderto move the shaft portion 64 outwardly, thereby changing the position ofthe valve seat 73 and relieving or reducing the force of the compressionspring 81. Following this action, the user then has a furtherpredetermined quantity of breathable gas still remaining in the tank 12and he may utilize this quantity during his return to the surface,

I claim:

1. A breathable gas regulating device comprising: first passage meansfor conducting breathable gas from a source to a point of use; a chamberin said device; second passage means for conducting expired gas fromsaid point of use to said chamber; a valve for controlling gas flowoutwardly from said chamber; a movable wall forming one side of saidchamber, said movable wall being subjected on one side to the pressureof a surrounding fluid medium; valve means for controlling the flow ofbreathable gas through said first passage means; means tending to resistopening movement of said valve means; lever means operatively associatedwith said movable wall for opening said valve means upon a reduction inthe pressure of said expired gas in said second passage means and insaid chamber, thereby to permit flow of said breathable gas through saidfirst passage means; and means responsive to changes in the pressure ofthe breathable gas at said source for varying the position at which saidvalve means is opened by said lever means.

2. A breathable gas regulating device comprising: first passage meansfor conducting breathable gas from a source to a point of use; a chamberin said device; second passage means for conducting expired gas fromsaid point of use to said chamber; a valve for controlling gas flowoutwardly from said chamber; a movable Wall forming one side of saidchamber, said movable wall being subjected on one side to the pressureof a surrounding fluid medium; valve means for controlling the fiow ofbreathable gas through said first passage means; means tending to resistopening movement of said valve means; lever means adapted for engagementwith one side of said movable wall for opening said valve means upon areduction in the pressure of said expired gas in said second passagemeans and in said chamber, thereby to permit flow of said breathable gasthrough said first passage means; and means responsive to changes in thepressure of the breathable gas at said source for varying the positionat which said valve means is opened by said lever means.

3. A breathable gas regulating device comprising: first passage meansfor conducting reathable gas from a source to a point of use; a chamberin said device; second passage means for conducting expired gas fromsaid point of use to said chamber; an exhalation valve for controllinggas fiow outwardly from said chamber; a movable wall forming one side ofsaid chamber, said movable wall being subjected on one side to thepressure of a surrounding fluid medium; a fiow control valve for controlling the flow of breathable gas through said first passage means; afloating valve seat for said fiow control valve; lever means operativelyassociated with said movable Wall for opening said flow control valveupon a reduction in the pressure of said expired gas in said secondpassage means and in said chamber, thereby to permit flow of saidbreathable gas through said first passage means; fulcrum means for saidlever means, said fulcrum means being movable in accordance withmovement of said floating valve seat;-and means for positioning saidfulcrum means and said valve seat relative to "8 said movable wall inresponse to changes in the pressure of said breathable gas from saidsource.

4. A breathable gas regulating device comprising; first passage meansfor conducting breathable gas from a source to a point of use; a chamberin said device; second passage means for conducting expired gas fromsaid point of use to said chamber; an exhalation valve for controllinggas fiow outwardly from said chamber; a movable wall forming one side ofsaid chamber, said movable wall being subjected on one sideto thepressure of a surrounding fiuid medium; a flow control valve forcontrolling the flow of breathable gas through said first pas sagemeans; a floating valve seat for said flow control valve; lever meansadapted for engagement with one side of said movable wall for openingsaid flow control valve upon a reduction in the pressure of said expiredgas in said second passage means and in said chamber, thereby to permitflow of said breathable gas through said first passage means; fulcrummeans for said lever means, said fulcrum means being movable inaccordance with movement of said floating valve seat; and means forpositioning said fulcrum means and said valve seat relative to saidmovable Wall in response to changes in the pressure of said breathablegas from said source.

5. A breathable gas regulating device comprising: first passage meansfor conducting breathable gas from a source to a point of use; a chamberin said device; second passage means for conducting expired gas fromsaid point of use to said chamber; an exhalation valve for controllinggas flow outwardly from said chamber; a movable wall forming one side ofsaid chamber, said movable wall being subjected on one side to thepressure of a surrounding fluid medium; a flow control valve forcontrolling the flow of breathable gas through said first passage means,said flow control valve having an enlarged head portion; resilient meanstending to retain said flow control valve in a closed position; levermeans having end portions adapted for engagement with one side of saidmovable wall and other end portions extending for operative associationwith said enlarged head for opening said flow control valve upon areduction in the pressure of said expired gas in said second passagemeans and in said chamber, thereby to permit flow of said breathable gasthrough said first passage means; fulcrum means for said lever means,said fulcrum means being positioned intermediate said end portions ofsaid lever means; and means responsive to changes in the pressure of thebreathable gas at said source for varying the position at which saidvalve means is opened by said lever means.

6. A breathable gas regulating device comprising: first passage meansfor conducting a breathable gas from a source to a point of use; achamber in said device; second passage means for conducting expired gasfrom said point of use to said chamber; a check valve for controllingfluid flow from said chamber to the surrounding fluid; a movable wallforming one side of said chamber, said movable wall being subjected onone side to the pressure in said chamber and on the other side to thepressure of the surrounding fluid; valve means for controlling the fiowof breathable gas through said first passage means; means operablyassociated with said movable wall for opening said valve means upon areduction of the pressure in said second passage means and in saidchamber thereby to permit flow of said breathable gas through said firstpassage means; means operably associated with said valve means fordecreasing the force required to open said valve means as the pressureof said breathable gas is reduced through use thereof; and meansoperably associated with said last mentioned means for maintainingsubstantially uniform the force required for movement of said valveopening means by said movable wall.

7. In a breathable gas regulating device: a regulator; a first chamberassociated with said regulator for reception of a breathable gas from asource; valve means for controlling the flow of. said gas into saidfirst chamber;

inhalation conduit means for conducting breathable gas from said firstchamber to a point of use; a second chamber in said regulator;exhalation conduit means for conducting exhalation products from saidpoint of use to said second chamber; a movable wall having one sideexposed to the pressure in said second chamber, the other side of saidwall being exposed to the pressure of the surrounding fluid medium; acheck valve for controlling fluid flow from said second chamber; levermeans operably interconnecting said movable wall and said valve means,whereby, upon inhalation, a reducti-i-n pressure is created in saidexhalation conduit means and in said second chamber, thereby to movesaid movable wall and open said valve means to permit a flow ofbreathable gas into said first chamber and into said inhalation conduitmeans; and means having a movable fulcrum means for said lever means formaintaining substantially uniform the force required to move said levermeans regardless of changes in the pressure of said breathable gas fromsaid source.

'8. A breathable gas regulating device comprising: first passage meansfor conducting a breathable gas from a source to a point of use; achamber in said device; second passage means for conducting expired gasfrom said point of use to said chamber; a movable wall forming one sideof said chamber, said movable wall being subjected on one side to thepressure in said chamber and on the other side to the pressure of thesurrounding fluid medium; valve means for controlling the flow ofbreathable gas through said first passage means; lever means operablyassociated with said movable Wall for opening said valve means upon areduction of the pressure in said second passage means and in saidchamber, thereby to permit flow of said breathable gas through saidfirst passage means; means having a movable fulcrum means for said levermeans for maintaining substantially uniform the force required to movesaid lever means regardless of changes in the pressure of saidbreathable gas from said source; and means positioned upstream from saidvalve means for interrupting the flow of said breathable gas when thesource pressure thereof is reduced to a predetermined level.

9. In a breathable gas regulating device: a regulator; a first chamberin said regulator adapted for reception of a breathable gas from asource; valve means for controlling the flow of said gas into said firstchamber; a movable valve seat associated with said valve means; springmeans normally urging said seat away from said valve means; means tooppose the force of said spring means in response to the pressure ofsaid breathable gas; inhalation conduit means for conducting breathablegas from said first chamber to a point of use; a second chamber in saidregulator; exhalation conduit means for con ducting exhalation productsfrom said point of use to said second chamber; a movable wall having oneside exposed to the pressure in said second chamber, the other side ofsaid wall being exposed to the pressure of the surrounding fluid medium;a check valve for controlling fluid flow from said second chamber; levermeans operably interconnecting said movable wall and said valve means,whereby, upon inhalation, a reduction in pressure is created inexhalation conduit means and in said second chamber, thereby to movesaid movable wall and open said valve means to permit a flow ofbreathable gas into said first chamber and into said inhalation conduitmeans; and fulcrum means for said lever means, said fulcrum means beingoperably connected to said movable'valve seat and adapted for axialmovement therewith, thereby to maintain substantially uniform the forcerequired to move said lever means regardless of changes in the pressureof said breathable gas from said source.

10. A breathable gas regulating device comprising, in combination: aregulator body; a first chamber in said body; passage means forconducting a compressed breathable gas from a source to said firstchamber; a valve mem- ,10 ber in said passage means; a movable elementassociated with said valve member, said element having a valve seatoperably associated with said valve member; first spring means normallyurging said valve member toward said valve seat; pressure differentialarea means provided on said element, said area means being subjected tothe pressure of said breathable gas from said source, thereby to urgesaid element and said valve seat toward said valve member; second springmeans acting on said element in a direction to oppose the force ofsaidbreathable gas on said pressure differential area means; an inhalationconduit for conducting said breathable gas from said first chamber to apointof use; a second chamber formed in said body; an exhalation conduitfor conducting exhalation products from said point of use to said secondchamber; a diaphragm forming one wall of said second chamber, saiddiaphragm having one side exposed to the pressure in said second chamberand the other side exposed to the pressure of the surrounding fluidmedium; a check valve for controlling fluid flow from said secondchamber; a plurality of levers engaging one side of said diaphragm andoperable by movement of said diaphragm in response to an inhalationproduced reduction in pressure in said exhalation conduit and in saidsecond chamber to lift said valve member from said valve seat, therebyto permit flow of breathable gas into said first chamber and into saidinhalation conduit; and fulcrum means for said levers, said fulcrummeansbeing operably connected to said movable element and adapted foraxial movement therewith, thereby to maintain substantially uniform theforce required to move said levers regardless of changes in the pressureof said breathable gas from said source.

11. A breathable gaszregulating device comprising, in

combination: a regulator body; a first chamber in said body; a source ofcompressed breathable gas; passage means for conducting said breathablegas from said source to said first chamber; a valve member in saidpassage means; a movable element associated associated with said valvemember, said element having a valve seat operably associated with saidvalve member; first spring means normally urging said valve membertoward said valve seat; pressure differential area means provided onsaid element, said area means being subjected to the pressure of saidbreathable gas from said source, thereby to urge said element and saidvalve seat toward said valve member; second spring means acting on saidelement in a direction to oppose the forced said breathable gas on saidpressure differential area means; an inhalation conduit for conductingsaid breathable gas from said first chamber to a point of use; a secondchamber formed in said body, said valvemember extending into said secondchamber; an exhalation conduit for conducting exhalation products fromsaid point of use to said second chamber; a diaphragm forming one wallof said second chamber, said diaphragm having one side exposed to thepressure in said second chamber and the other side exposed to'thepressure of the surrounding fluid medium; a check valve for controllingfluid flow from said second chamber; a plurality of levers engageablewith one side of said diaphragm and operable by movement of saiddiaphragm in response to an inhalation produced reduction in pressure insaidexhalation conduit and in said second chamber to lift said valvemember from said valve seat, thereby to permit a flow of breathable gasinto said first chamber and into said inhalation conduit; fulcrum meansfor said levers, said fulcrum means being operably connected to saidmovable element and adapted for axial movement therewith, thereby tomaintain substantially uniform the force required to move said leversregardless of changes in the pressure of said breathable gas from saidsource; and means positioned between said valve member and said sourceof breathable gas to interrupt the flow of said gas when the gaspressure of said source is reduced to a predetermined level.

12. In a breathable gas regulating apparatus having a respirationresponsive movable wall and a valve member for controlling flow of abreathable. gas from a source to a point of use, means operable inresponse to movement of said movable Wall for opening'said valve membercomprising: lever means operably engageable with said movable wall andextending to said valve member; fulcrum means for said lever means; andmeans for maintaining substantially uniform the force. required to movesaid lever means regardless of changes in the pressure of said gas fromsaid source, said means having means responsive to changes in pressureof the gas at the source for shifting the position of said fulcrummeans.

13. In a breathable gas regulating apparatushaving a respirationresponsive movable wall and-a valve member for controlling flow of abreathable gas from a source to a point of use, means operable inresponse to movement of said movable wall for opening said valve membercomprising: a plurality of levers operably engagable with one side ofsaid movable wall and extending to said valve member; fulcrum means forsaid levers; and means for maintaining substantially uniform the forcerequired to move said levers regardless of changes in said gas pressure,said means having means responsive to changes in pressure at said gassource for shifting the position of said fulcrum means.

14. In a breathable gas regulating apparatus having a respirationresponsive movable wall, a valve member and a cooperating pressureresponsive floating valve seat for controlling flow of a breathable gasfrom a source to a point of use, means operable in response to movementof said movable wall for opening said valve member comprising: aplurality of levers operably engagable with one side of said movablewall adjacent the outer periphery thereof and extending to said valvemember; fulcrum means for said levers, said fulcrum means beingoperatively associated with said floating valve seat; and means forpositioning said fulcrum means in response to changes in the pressure ofsaid gas from said source and relative to said movable wall, thereby tomaintain substantially uniform the force required to move said leversregardless of said changes in said gas pressure.

15. In a breathable gas regulator of the type having a respirationresponsive movable wall: valve means for controlling the flow of abreathable gas from a source into said regulator; an element engagingsaid valve means and tending to resist opening movement thereof; meansresponsive to pressure of gas at said source to move said valve meansand vary the eifective resistance of said element, a reduction in gaspressure at said source causing movement of said valve in a direction toproportionally decrease the resistance of said element; and actuatingmeans operable in response to movement of said movable wall for movingsaid valve means toward an open position in opposition to saidresistance element.

16. In a breathable gas regulator of the type having a respirationresponsive movable wall: valve means for controlling the flow of abreathable gas from a source into said regulator; a spring tending toresist opening movement of said valve means; means responsive to thepressure of gas at said source to move said valve means and vary theetfective resistance of said spring, a reduction in gas pressure at saidsource causing movement of said valve means in a direction toproportionally decrease the resistance of said spring; and actuatingmeans operable in response to movement of said movable wall for movingsaid valve member toward an open position in opposition to said spring.

17. In a breathable gas regulator of the type having a respirationresponsive movable wall: valve means for controlling the flow of abreathable gas from a source into said regulator; means forming a valveseat for said valve means, said seat-forming means being disposed formovement in response to variations in pressure of the gas at saidsource; resilient means tending to resist movement of said valve meanstoward an open position; actuating means operable in response tomovement of said movable wall to move said valve member toward an openposition in opposition to said resilient means;'and means movablesimultaneously with said valve seat-forming means for maintainingpredetermined characteristics of said actuating means regardless ofvariations in gas pressure at said source.

t8. In a breathable gas regulator of the type having a' respirationresponsive movable wall: valve means for controlling the flow of abreathable gas from a source into said regulator; means forming a valveseat for said valve means; resilient means tending to resist movement ofsaid valve means toward an open position, said valveseat-forming meansbeing disposed for movement in response to variations in pressure of thegas at said source to change the effective resistance of said resilientmeans; actuating means operable in response to movement of said movablewall to move said valve means toward an open position in opposition tosaid resilient means; and means movable with said valve seat-formingmeans for maintaining predetermined relationships between said actuatingmeans and said valve member during movement of said valve seat-formingmeans.

19. In a breathable gas regulator of the type having a respirationresponsive movable wall: valve means for controlling the flow of abreathable gas from a source into said regulator; means forming a valveseat for said valve means; resilient means tending to urge said valvemeans toward said seat; means on said valve seat-forming meansresponsive to changes in gas pressure at said source tomove said valveseat-forming means and valve means in a direction to change theeffective resistance of said re silient means in direct proportion tothe change in gas pressure; actuating means operable in response tomovement of said movable wall to move said valve means' toward an openposition in opposition to said resilient means; and means movablesimultaneously with said valve seat-forming means for maintainingpredeterminedJre'lations of said actuating means and said valve memberin different positions of said valve seat-forming means. 20. In abreathable gas regulator of the type having a respiration responsivemovable wall: a valve element for controlling the flow of a breathablegas from a source into said regulator, said valve element having an areaexposed to source pressure which tends to move said valve element towardan open position; means forminga float ing seat for said valve element;resilient means tending to urge said valve element toward said seat witha force slightly exceeding the force exerted by said pressure; a surfacearea on said seat-forming means exposed to source pressure, suchpressure tending to cause movement of said seat-forming means and valveelement, a reduction in source pressure causing movement of saidseat-forming means and valve element to reduce the efiective force ofsaid resilient means in direct proportion to said pressure reduction;actuating means operative in response to predetermined movement of saidmovable wall to move saidv valve toward open position in opposition tosaid resilient means; and means movable in unison with said valveseatforming means for maintaining predetermined relations between saidactuating means and said valve element regardless of the change ineffective force of said resilient means.

References Cited in the file of this patent UNITED STATES PATENTS2,269,500 Wildhack Jan. 13, 1942 UNITED STATES PATENT OFFICE CERTIFICATEOF CORRECTION Patent No. 2,828,739 April 1, 1958 Robert ,Kimes 7 It ishereby certified that error appears in the printed specification of theabove numbered patent requiring correction and that the said LettersPatent should read as corrected below.

Column 5 line 25, for "hardness" read harness column 10, line 38, strikeout "associated", second occurrence.

Signed and sealed this 27th day or May 1958.

(SEAL) Attest:

KARL AXLINE ROBERT c. WATSON Attesting Officer Conmissioner of Patents

